1. Technical Field
The present invention relates to a light emitting device and a projector.
2. Related Art
A semiconductor light emitting device, such as a semiconductor laser and a super luminescent diode (hereinafter also referred to as “SLD”), is used, for example, as a light source of a projector. In the optical waveguide in a semiconductor laser and an SLD, light is amplified along the path toward a light exiting surface through which the light exits. Therefore, in the vicinity of the light exiting surface, gain saturation occurs due to shortage of the amount of carrier to be converted into light, resulting in a decrease in the output in some cases.
For example, WO 2013/171950 describes that in a semiconductor laser, use of a tapered stripe structure, in which the width of the optical waveguide gradually increases in the direction toward the resonator, prevents an extreme bias of the electric field intensity of the light in the direction toward the resonator so that the degree of spatial hole burning is reduced for suppression of the gain saturation. WO 2013/171950 further describes that setting the width of the contact layer to be smaller than the width of the ridge stripe reduces the amount of current injected into the horizontally opposite ends of the ridge stripe so that the degree of spatial hole burning of the carrier in the horizontal direction is suppressed for suppression of the gain saturation.
In WO 2013/171950, however, the amount of current injection is optimized in a semiconductor laser, and the distribution of the amount of current injection optimized in an SLD differs from that in a semiconductor laser.